Poorly treated urban and industrial effluents and overdevelopment, both of housing and tourism, are the main problems along Greece’s coastline. The European Environment Agency reports that local environmental problems are caused by the lack or inadequacy of waste processing plants for urban and industrial waste. The report says the following areas in Greece have the worst coastal pollution. Elefsina Bay. It has untreated waste from 1,000 industrial plants including shipyards, refineries, cement, paper mills, as well as high concentrations of heavy metals in water, sediments and some biota (mussels). Saronic Gulf. It has primary treated effluents from the capital and industrial effluents, as well as occasional signs of eutrophication. Thermaic Gulf. It has processed industrial and urban waste from the city of Thessaloniki and the Kalohori industrial region. Pagasitic Gulf. It has treated urban waste and industrial waste, as well as agricultural runoff through the Pineos River. Amvrakikos Gulf. It has treated industrial and urban waste and agricultural runoff (nitrogen). Patras and Iraklion. Waters in both areas contain urban and industrial effluents. Gulf of Argos. It has excessive nitrogen load from farmland.